Older cars did not have a fan controller for changing fan speed. (Radiator Fan Controller, RFC) What was used instead was a fan switch or mechanical control. This proved inadequate and had low efficiency for heat transfer and cooling. It was also difficult to adjust fan speed and amount of cooling. The generated power being low and economically wasteful the old methods were unable to adapt to modern cars. With new RFC, it is now possible to increase the efficiency of the engine cooling system to be more sensitive and reliable.
One example of an electric motor fan control system for vehicle is shown in Yamada U.S. Pat. No. 5,133,302 issued Jul. 28, 1992, which claims foreign priority from Japanese application 2-247990 filed Sep. 18, 1990 both disclosures of which are incorporated herein by reference. Yamada teaches a fan control system of a vehicle for controlling an electric motor fan for cooling a radiator. Cooling fan power management systems were also taught in Claypole U.S. Pat. No. 4,425,766 issued Jan. 17, 1984, the disclosure of which is incorporated herein by reference. Claypole taught a pulse width modulated voltage control device for controlling the voltage applied to the cooling fan motor from the vehicle. Naitoh in U.S. Pat. No. 5,018,484 issued May 28, 1991 shows a variety of temperature sensors for controlling an electric cooling fan of an automotive vehicle, the disclosure of which is incorporated herein by reference. A variety of these fan control systems are known in the art. These fan control circuits can be put on printed circuit board.
But presently, current radiator fan controllers have integrated the main body with the wire harness bonded by cyclooxy resin. The disadvantage is not only cosmetic but the assembly process is old and inefficient. Sealing with resin requires a long time to cure and if testing finds a problem, the entire controller and wire harness is wasted which increases production cost. Also, if during use there is a problem, the user can only replace the entire unit.